1. Field of the Invention
The present invention relates to a vibration-isolating and sound-isolating system for a vehicle for reducing the vibration provided by an engine of an automobile and noises such as, exhaust sound and intake sound in the engine.
2. Description of the Related Art
A conventional active vibration-isolating system used in an engine mount of an automobile is described in Japanese Patent Application Laid-open No. 9-273589. The active vibration-isolating system is fixed at its upper end to an engine which is a vibration source and at its lower end to a vehicle body frame through a load sensor. A load of vibration transmitted from the engine to the vehicle body frame is detected by the load sensor, and the active vibration-isolating system is controlled so as to eliminate a change in the load, thereby achieving a vibration-isolating effect.
In the conventional active vibration-isolating system, the vibration transmitted from the engine to the vehicle body frame can be reduced, but the intake sound and the exhaust sound which are a vibration and a noise not passing through this transmission path cannot be reduced. In the conventional system, vibration-isolating control corresponding to the dispersion and deterioration of parts can be carried out by adaptive control, but the cost is increased due to the use of the load sensor for carrying out the adaptive control.